\begin{tikzpicture}
    \begin{scope}
        \tkzDefPoints{0/0/B, 3/0/C, 0.8/1.5/A, 2.2/1.5/D}
        \tkzDrawPolygon(A,B,C,D)
        \tkzLabelPoints[left](A,B)
        \tkzLabelPoints[right](D,C)

        \tkzDefLine[parallel=through A](D,C)  \tkzGetPoint{e}
        \tkzInterLL(A,e)(B,C)  \tkzGetPoint{E}
        \tkzDrawSegment[dashed](A,E)
        \tkzLabelPoints[below](E)
    \end{scope}

    \begin{scope}[xshift=5cm]
        \tkzDefPoints{0/0/B, 3/0/C, 0.8/1.5/A, 2.2/1.5/D}
        \tkzDrawPolygon(A,B,C,D)
        \tkzLabelPoints[left](A,B)
        \tkzLabelPoints[right](D,C)

        \tkzDefLine[altitude](B,A,C)  \tkzGetPoint{E}
        \tkzDefLine[altitude](B,D,C)  \tkzGetPoint{F}
        \tkzDrawSegments[dashed](A,E  D,F)
        \tkzMarkRightAngle(A,E,B)
        \tkzMarkRightAngle(D,F,C)
        \tkzLabelPoints[below](E,F)
    \end{scope}
\end{tikzpicture}

